Obesity, as defined by a body mass index (BMI) of 30 kg/m2 or more, is a rapidly growing problem, currently affecting more than 30% of adults in the United States. Morbid obesity, as defined by a body mass index of 40 kg/m2 or more or a BMI of 35 kg/m2 or more in the presence of co-morbidities is also prevalent, affecting 3.1% of men and 6.7% of women. Obesity is commonly associated with many serious medical disorders including heart disease, diabetes, hypertension, hyperlipidemia, hypercholesterolemia, osteoarthritis and sleep apnea. In addition, approximately 300,000 adults in the U.S. die each year due to obesity-related causes.
The primary treatment objective for obese patients is weight reduction, which can improve co-morbid conditions and also reduces risk factors for disease. Even moderate weight loss (5%-10% of initial weight) produces health benefits and has been associated with marked reductions in the risk for the medical disorders listed above. While non-operative and pharmacologic weight loss therapies have met with only limited success, surgical intervention for morbid obesity, most frequently gastric bypass, is becoming increasingly common. However, the decision to undergo gastric bypass is a difficult one. Patients who choose to undergo gastric bypass are making a serious commitment to permanent life-style changes and are at risk for developing metabolic/nutritional complications resulting from the long-term malabsorptive effects of gastric bypass and food intake restriction. Long-term complications of gastric bypass including anemia secondary to iron or B12 deficiency, mineral deficiencies (hypokalemia and hypomagnesia) and bone disease associated with secondary hyperparathyroidism are not uncommon. These conditions can be serious thereby necessitating lifelong medical follow-up to monitor for such events.
Although various procedures exist for the surgical treatment of morbid obesity, the Roux-en-Y gastric bypass (RYGB) has been identified as the gold standard for morbidly obese patients when non-invasive interventions have failed. The RYGB procedure entails the creation of a small gastric pouch to which the distal jejunum is attached via creation of an anastomosis referred to as a gastrojejunostomy (GJ). The procedure excludes more than 95% of the stomach, all of the duodenum and the proximal jejunum from digestive continuity. Weight loss is thought to result from reduced intake volume due to the small gastric pouch and limited GJ diameter, as well as from malabsorption due to the bypass of the proximal jejunum. The procedure is associated with a mean of 65-75% excess weight loss with 1% mortality and 10% morbidity.
Despite the favorable safety and effectiveness profile of the RYGB procedure, technical complications and inadequate weight loss may occur. Serious complications are not uncommon after open bariatric procedures. Adhesion formation may contribute to small bowel obstructions, which may require an additional operation for the patient. Incisional hernias are another complication associated with abdominal surgical procedures and have been shown to occur at a much higher rate after open gastric bypass surgery than after laparoscopic bypass surgery.
The significant morbidity associated with traditional weight loss surgery emphasizes the importance of the development of minimally invasive interventions that will result in patient weight loss, which may improve co-morbid conditions and also reduce risk factors for disease. Additionally, a minimally invasive or intragastrointestinal approach will minimize or eliminate many of the risks associated with open and laparoscopic procedures.